# Network Address Translation | ![img \|150](https://upload.wikimedia.org/wikipedia/commons/thumb/c/c7/NAT_Concept-en.svg/320px-NAT_Concept-en.svg.png) | **Network Address** translation (NAT) is a method of mapping an IP address space into another by modifying network address information in the IP header of packets while they are in transit across a traffic routing device. The technique was originally used to bypass the need to assign a new address to every host when a network was moved, or when the upstream Internet service provider was replaced, but could not route the network's address space. It has become a popular and essential tool in conserving global address space in the face of IPv4 address exhaustion. One Internet-routable IP address of a NAT gateway can be used for an entire private network. | | ----------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | | wikipedia:: [Network address translation](https://en.wikipedia.org/wiki/Network_address_translation) | [[Subnet]] [[NAT-PMP]]